Identification of a Natural Source of Resistance to Watermelon Chlorotic Stunt Virus in an Indigenous Accession of Cucumis Melo Var. Agrestis

Watermelon chlorotic stunt virus (WCSV) is among the most important viral diseases of the family Cucurbitaceae. It is a bipartite begomovirus (DNA-A and DNA-B genome components) that belongs to the family Geminividae (Walkely et al., 1990). It causes severe crop losses, particularly in watermelon and melon (Lecoq et al.,1994). In Sudan, WCSV causes high reduction in yield and quality of watermelon, melon, snake cucumber and squashes. Leaves of infected plants are crinkled, stunted and develop striking chlorotic mottle. The whole plant looked stunted and chlorotic and may be devoid of marketable fruits (Walkely et al., 1990). Resistance to major diseases is very common among indigenous Sudanese melons, Tibish and agrestis (C. melo var. agrestis), compared to other melon types (Mohamed, 2000).    Experiments were conducted at the University of Gezira Research Farm in April (1996-1997) to identify a natural source of resistance to watermelon chlorotic stunt virus in Cucumis melo L. The screened material included: 101 accessions of C. melo var. cantalupensis and C. melo var flexuousus collected in Sudan; nine accessions belong to the indigenous Humaid type (C. melo var. agrestis) and eleven introduced lines such as P1 313970, P1 131375, Pl 255478, Vedrantais, Nantais Oblong, MR-I, Isoblon, Virgos, Margot and Zumo. The inoculation pressure of the virus in the field was increased by growing plants of the susceptible watermelon cultivar "Sugar Baby", obtained from Peto Seed Company, about one month before conducting the screening experiments

Genetics and Stability of Resistance to Watermelon Chlorotic Stunt Virus in Melon (Cucumis Melo L).

Experiments were carried out under field conditions at the University Gezira Research Farm, Sudan and the agroinoculation and green houses conditions in France (le Centre National de la Recherche Scientifique (CNRS*) and le Institut National de la Recherche Agronomique (INRA**) to study the inheritance and stability of resistance to watermelon chlorotic stunt virus (WCSV) in melon (C. melo L.).   The techniques of autoradiography, using the ratioactive WCSV P32, probe was used to detect WCSV in plant tissue and the phospho-imager machine was used to obtain quantified results of DNA particles within the examined plant tissue. The results indicated the presence of one dominant gene and another recessive independent gene controlling WCSV resistance in the resistant lines P1414723, P1124112 and HSD2445- 005. Multi-locational trials on resistant lines under natural field conditions revealed that the resistance to WCSV in melon is uniform and stable. Results of studying the movement of the virus within the plant tissues indicated that the blockage in the plant indigenous trafficking system was one of the mechanisms that are involved in plant resistance to WCSV in the lines P1414723, P1282448, P1124440, Pl 124112, 90625 and HSD 2445-005

Cure of post Kala-azar dermal leishmaniasis with paromomycin/sodium stibogluconate combination: a proof of concept

Background: Post kala-azar dermal leishmaniasis (PKDL) is  a  recognized  dermatologic  complication  of  successfully  treated  visceral  leishmaniasis  (VL). PKDL lesions are suspected to be important reservoirs for VL transmission in Sudan. Prolonged treatment schedules, feeling of general well-being and the social stigmata of PKDL prevent most patients seeking treatment. The mainstay of treatment is cardiotoxic sodium stibogluconate (SSG) for 60-120 days. Recently, liposomal amphotericin B (Ambisome®) and immunochemotherapy gave promising results. Ambisome® is expensive and difficult to prepare under field conditions. Paromomycin/SSG combination has been shown to be safe, efficacious and can save time in VL treatment. This study aims to prove that Paromomycin/SSG combination can cure and reduce PKDL treatment duration.Methods:We are reporting nine cases of patients with PKDL lesions of ≥6 months duration who were diagnosed by clinical signs, histopathological/immunohistochemical and PCR.Results: Patients’ mean age was 11.7 ± 4.3 years. A third of the patients (3/9; 33.3%) who failed previous SSG treatment of 2-3 months duration responded completely to 40 days of paromomycin/SSG combination. The majority of patients (5/9; 55.6%) responded completely to 30 days of the combination. One patient (1/9; 11.1%) relapsed following 30 days paromomycin/SSG combination.Conclusion:It was concluded that paromomycin/SSG combination for 30 days is time-saving, safe and efficacious for PKDL treatment.

Phyllodie de la féverole au Soudan. II - Détection de la maladie par la microscopie photonique : fluorescence, lumière normale, contraste interférentiel et mise en évidence des MLOs en microscopie électronique par transmission

International audienceSeveral techniques of fluorescence, light and electron microscopy were used to detect MLOs in sieve tube elements of phyllody diseased faba bean plants. The DNA-binding fluorochrome Bisbenzimid H 33258 provided satisfactory results when used with sections prepared from fresh materials using freezing microtome or cryostat and with fixed materials embedded in paraffin or historesin. While sections from fresh materials provided rapid means of indexing, historesin and paraffin have the advantage of better preservation of anatomical characteristics of plant tissues. This was particularly the case of historesin since sections were processed without removing the embedding medium. Semi-thin sections (250-350 nm) prepared from epoxy resin-embedded plant tissue are not amenable to staining with DNA-specific fluorochromes, hence they could not be used for fluorescence microscopy. Alternatively, 2 methods of ordinary light microscopy could be utilized with such sections. The first was to examine unstained sections in a light microscope with differential interference contrast of Nomarski, and the second implied staining with thionin and acridine orange and observation in a bright field microscope. Both techniques, though non-specific to MLO provided additional tool in cytopathological studies of diseased plants and could be useful in determining areas meriting further examination in electron microscopy. The presence of MLOs in plant tissues, used for light and fluorescence microscopy, was confirmed in ultrathin and semi-thin sections observed by transmission electron microscopy.Plusieurs techniques de microscopie photonique en fluorescence et en lumière normale ainsi que de microscopie électronique ont été utilisées pour détecter les MLO à l’intérieur des tubes criblés de la féverole atteinte de phyllodie. Un fluorochrome spécifique de l’ADN, Bisbenzimid H 33258 ou réactif de Hoechst, a donné des résultats satisfaisants quel que soit le mode de préparation du matériel végétal : tissu frais coupé au cryostat, tissu fixé et inclus dans la paraffine ou dans l’historésine. Les coupes préparées à partir de matériel frais ont permis l’indexage rapide de l’infection alors que l’inclusion dans la paraffine et surtout dans l’historésine a l’avantage de faciliter la caractérisation des structures anatomiques des tissus. L’historésine présente un intérêt particulier car les coupes peuvent être colorées en présence du milieu d’inclusion. De plus, des coupes semi-fines de 250 à 350 nm d’épaisseur ont été préparées à partir de tissus fixés et inclus dans une résine époxy. Elles ne présentent pas de fluorescence. Aussi, 2 méthodes de microscopie photonique en lumière normale ont été alternativement employées : la première consiste en l’observation des coupes non colorées en contraste interférentiel de Nomarski et, la deuxième utilise la coloration par la thionine et l’acridine orange. Ces 2 techniques, bien que non spécifiques, facilitent la localisation des zones qui nécessitent une étude ultérieure en microscopie électronique. La présence des MLO à l’intérieur des tubes criblés des tissus malades a été confirmée sur les coupes ultrafines observées en microscopie électronique par transmission

Phyllody of faba bean in the Sudan. II. — Detection of the disease by light microscopy: fluorescence, bright field, interference contrast and observation of MLOs by transmission electron microscopy

Several techniques of fluorescence, light and electron microscopy were used to detect MLOs in sieve tube elements of phyllody diseased faba bean plants. The DNA-binding fluorochrome Bisbenzimid H 33258 provided satisfactory results when used with sections prepared from fresh materials using freezing microtome or cryostat and with fixed materials embedded in paraffin or historesin. While sections from fresh materials provided rapid means of indexing, historesin and paraffin have the advantage of better preservation of anatomical characteristics of plant tissues. This was particularly the case of historesin since sections were processed without removing the embedding medium. Semi-thin sections (250-350 nm) prepared from epoxy resin-embedded plant tissue are not amenable to staining with DNA-specific fluorochromes, hence they could not be used for fluorescence microscopy. Alternatively, 2 methods of ordinary light microscopy could be utilized with such sections. The first was to examine unstained sections in a light microscope with differential interference contrast of Nomarski, and the second implied staining with thionin and acridine orange and observation in a bright field microscope. Both techniques, though non-specific to MLO provided additional tool in cytopathological studies of diseased plants and could be useful in determining areas meriting further examination in electron microscopy. The presence of MLOs in plant tissues, used for light and fluorescence microscopy, was confirmed in ultrathin and semi-thin sections observed by transmission electron microscopy.Plusieurs techniques de microscopie photonique en fluorescence et en lumière normale ainsi que de microscopie électronique ont été utilisées pour détecter les MLO à l’intérieur des tubes criblés de la féverole atteinte de phyllodie. Un fluorochrome spécifique de l’ADN, Bisbenzimid H 33258 ou réactif de Hoechst, a donné des résultats satisfaisants quel que soit le mode de préparation du matériel végétal : tissu frais coupé au cryostat, tissu fixé et inclus dans la paraffine ou dans l’historésine. Les coupes préparées à partir de matériel frais ont permis l’indexage rapide de l’infection alors que l’inclusion dans la paraffine et surtout dans l’historésine a l’avantage de faciliter la caractérisation des structures anatomiques des tissus. L’historésine présente un intérêt particulier car les coupes peuvent être colorées en présence du milieu d’inclusion. De plus, des coupes semi-fines de 250 à 350 nm d’épaisseur ont été préparées à partir de tissus fixés et inclus dans une résine époxy. Elles ne présentent pas de fluorescence. Aussi, 2 méthodes de microscopie photonique en lumière normale ont été alternativement employées : la première consiste en l’observation des coupes non colorées en contraste interférentiel de Nomarski et, la deuxième utilise la coloration par la thionine et l’acridine orange. Ces 2 techniques, bien que non spécifiques, facilitent la localisation des zones qui nécessitent une étude ultérieure en microscopie électronique. La présence des MLO à l’intérieur des tubes criblés des tissus malades a été confirmée sur les coupes ultrafines observées en microscopie électronique par transmission

Genetic diversity of Ustilago scitaminea (Syd.) Sudan isolates evaluated by differential sugarcane varieties under field conditions

Field experiments were conducted at the Sugarcane Research Centre, Guneid (lat. 15oN, long. 33oE), in seasons 2006/07 and 2008/09. The objectives were to biologically characterize six Sudan isolates of Ustilago scitaminea (Syd.) collected from different geographic locations; and, were designated as: GN1 (Guneid, NCO 376 isolate); GN2 (Guneid, CO 527 isolate); GN3 (Guneid, CO 6806 isolate); SN (Sennar, CO 527 isolate); AB (Abbasiya, isolate from mixed varieties); and NH (New-Halfa, CO 527/ CO 997 isolate) by a set of 25 differential sugarcane varieties. All inoculations were done artificially by Taiwanese pin prick method (TPPM) and dip method (DM). Results identified four pathotypes. The first and second groups; GN1, GN2 and GN3 occur in Guneid, while the third group; SN and  NH occur in Sennar and New Halfa and the fourth group AB in Abbasiya (Kenana/ Assalaya area). All four pathotypes were highly similar in pathogenicity and have relatedness percentages of 60 to 85%. Isolates GN1, NH and AB were slightly distinct and associated with virulence and, AB with avirulence, respectively. The other isolates were difficult to separate. Therefore, the absence of an isolate of high virulence indicates that the occurrence of smut in the current resistant variety CO 6806 is largely due to variety degradation/or resistance erosion and not due to a pathogenic entity of the smut pathogen. The study recommends an expanded screening program for smut resistance evaluation to make available a large number of resistant sugarcane varieties coupled with careful selection of seed cane      أجريت هذه التجربة بمركز بحوث قصب السكر – الجنيد (خط عرض 015 ش، طول  033ق) على مدى ثلاثه مواسم متتالية 2006/07، 2007/ 08 و2008/09 بهدف التمييز بايولوجياً لعدد سته عزلات مختلفة من الفطر U. scitaminea متواجدة فى السودان جمعت من مناطق جغرافية مختلفة سميت بالجنيد 1 (GN1) – وهو عزل من منطقة الجنيد من الصنف   - NCO376 ،الجنيد 2 (GN2 ) – عزل من منطقة الجنيد من الصنف CO527 - ، الجنيد 3(GN3) – عزل من منطقة الجنيد من الصنف CO6806  -، والصنف سنار – عزل من منطقة سنار (SN) من الصنف  527CO - ، عباسية (AB) – عزل من منطقة العباسية من هجن مختلفة من قصب السكر - ، حلفا الجديدة (NH) عزل من منطقة حلفا الجديدة من الأصناف CO527،و CO997. ميزت بايولوجيا بأستخدام طقم مكون من 25 صنف محلى من قصب السكر . أحدثت عدوى صناعية بالمرض فى أصناف قصب السكر المختبرة بطريقتي إحداث الثقب و الغمر. أوضحت النتائج المختلفة أن عزلات الفطر U. scitaminea  الموجودة بالسودان متشابهة. عموما قسمت لأربعة سلالات ممرضة والتى عرفت ب :- السلالة الاولي والثانية  .GN1 GN2و GN3 فى الجنيد .السلالة الثالثة  SN و NH وجدا فى كل من حلفا الجديدة وسنار .السلالة الرابعة AB وجدت فى المنطقة الجغرافية لعسلايا وكنانة . وجدت كل العزلات الممرضة الأربعة شديدة التشابه من حيث الامراضية  وذات درجة قرابة 60-85 % ، .عموما   GN1و  NH مختلفة بدرجة طفيفة فى حين أن الاخريات من الصعب التفريق بينهما.  فالعزل GN1 ذو قدرة طفيفة فى شدة إحداث المرض  والعزل AB ضعيف القدرة فى شدة إحداث المرض جنبا للعزلGN2 , GN3 والعزل SN متوسط فى شدة إحداث المرض. عموما عدم وجود عزل فطرى شديد فى حدة الإصابة فى قصب السكر يدل على أن بعض حالات الإصابة مؤخرا فى الصنف CO6806 المعروف بشدة المقاومة لمرض التفحم السوطى يدل على تدهور فى الصنف نفسه وليس بسبب العزل المسبب للمرض . توصى الدراسة بوضع وتحديد برنامج لتقييم دورى لمستوى مقاومة الأصناف المزروعة ضد مرض التفحم السوطى لوضع رؤية واسعة لأصناف مقاومة من قصب السكر . بالإضافة إلى إستمرارية الممارسات الحقلية الجارية مع التجديد والإهتمام باختيار تقاوى قصب السكر

Snake melon asteroid mosaic virus, a tentative new member of the genus Sobemovirus infecting cucurbits

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699International audienceA virus isolate (Su-95-67) was obtained from a snake melon (Cucumis melo var. flexuosus) plant presenting severe chlorotic spots, mosaic,stunting, and leaf deformations collected in Eastern Sudan in 1995. Su-95-67 was easily mechanically transmissible and had a host range limited to a few cucurbit species. Isometric virus particles approximately 30 nm in diameter were observed in leaf dip preparations. A cytopathological study did not reveal alterations specific for a virus genus or family. A polyclonal antiserum was obtained and used in double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). Su-95-67 was transmitted by seed at a low rate, by the red melon beetle (Aulacophora foveicollis), but not by the melon aphid (Aphis gossypii. Because Su-95-67 shared several properties with sobemoviruses, generic Sobemovirus reverse-transcription polymerase chain reaction primers were developed. They allowed amplification of a 384-bp fragment from extracts of plants infected by two sobemoviruses or by Su-95-67 but not from healthy plants extracts. Sequence comparison confirmed that Su-95-67 belongs to a new tentative Sobemovirus species for which we propose the name Snake melon asteroid mosaic virus (SMAMV). DAS-ELISA tests conducted on extracts of virus-infected cucurbit plants collected from 1992 to 2003 revealed the presence of SMAMV in 10.2% of 600 samples originating from different regions of Sudan

Principaux virus des cucurbitacées au Soudan

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Characterization and occurrence of Zucchini yellow mosaic virus in Sudan

International audienceZucchini yellow mosaic potyvirus (ZYMV) was isolated in 1993 from a squash plant (Cucurbita pepo cv. Eskandrani) showing severe leaf and fruit distortions, collected in the Gezira region (Sudan). This isolate (ZYMV-Su) was found to be very closely serologically related if not identical to the type strain from Italy. The host range was mostly limited to Cucurbitaceae but systemic infection was found to occur on sesame (Sesamum indicum), an important cultivated crop in Sudan. ZYMV-Su induced mosaic symptoms on the resistant melon accession PI 414723, indicating that it belongs to pathotype 2, but did not cause wilting of melon cv. Dobulon. ZYMV-Su was efficiently transmitted by Myzus persicae and Aphis gossypii in a non-persistent manner. Surveys conducted from 1993 to 1995 revealed that ZYMV occurred in the major cucurbit growing areas in Sudan, in a diversity of crops and agroecosystems

Caractérisation d'un nouveau sobemovirus, le snake melon asteroid mosaic virus (SMAMV), infectant le melon. Communication orale

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